Printing cylinder with plate securing means



Jan. 20, 1970 'w. F. HUCK 3,490,369

PRINTING CYLINDER WITH PLATE SECURING MEANS Filed June 5, 1966 5 Sheets-Sheet 1 INVENTOR. WILLIAM F. HUCK ATTORNEY Jan. 20, 1970 Filed June 5, 1966 w. F. HUCK I 3,490,369

PRINTING CYLINDER WITH PLATE SECURING MEANS 5 Sheets-Sheet 8 IN VENTOR.

WILLIAM F. HUCK A TTORIV E Y PRINTING CYLINDER WITH PLATE SECURING MEANS 5 Sheets-Sheet 3 Filed June 5, 1966 INVENTOR WILLIAM F. HUCK ATTORNEY Jan. 20, 1970 w. FQHUCK PRINTING CYLINDER WITH PLATE SECURING MEANS 5 Sheets-Sheet 4 Filed June 5, 1966 INVENTOR.

WILLIAM F. HUCK AT HEY Jan. 20, 1970 w. F. Huck 3,490,369

PRINTING CYLINDER WITH PLATE SECURING MEANS Filed June 5, 1966 5 Sheets-Sheet '5 /57 8 w a? ms a 076% m 20 l )(Zl/ /46 we /20 Q #2 m V ,INVENTOR. WILLIAM F. HUCK ATTORNEY United States Patent 3,490,369 PRINTING CYLINDER WITH PLATE SECURING MEANS William F. Huck, 81 Greenway Terrace, Forest Hills, N.Y. 11375 Filed June 3, 1966, Ser. No. 555,104 Int. Cl. B411? 27/12 US. Cl. 101-378 Claims ABSTRACT OF THE DISCLOSURE Printing or like cylinders, especially intaglio printing and impression cylinders for rotary stamp or gravure presses, are made of sheet metal plates preformed to the curvature of a cylindrical body surface and held tightly thereto with outer edge portions of adjacent plates mating precisely to form a rigid cylindrical working surface free of gaps other than fine hairline cracks. The mating plate edges are undercut and grooved laterally along and beneath such outer edge portions, and are held in place by long grippers which have lateral flanges fitting into the entire lengths of the edge grooves. The grippers for axial plate edges are displaced radially outward with the plates thereon to release the plates for individual removal and replacement. Any gripped circumferential edges are released by relative axial displacement of the grippers engaging them. Intaglio plates are sized so that hairline imprints formed at their abutting edges will occur where the printed matter is to be cut, folded or perforated.

This invention relates generally to printing or like cylinders which require a substantially uninterrupted working surface, for example, as in intaglio printing cylinders.

In intaglio printing processes, the lines and figures to be reproduced are depressed or recessed in the working surface of the printing cylinder rather than being raised, as is the case in typography. The ink is applied to the surface of the printing cylinder either by rollers or by running the cylinder in an ink bath, as in gravure printing, whereupon the working surface of the printing cylinder is wiped clean leaving deposits of ink only in the recessed or itagliated portions of the working surface for application to the paper or other ink receptive material to be printed. Although intaglio printing provides imprints of uniquely high quality, its use has been limited generally to the printing of material that is not subject to change or revision of layout and where cost is not of primary importance.

The limited use of intaglio printing results mainly from the. nature of the printing cylinder traditionally employed therefor. Such intaglio printing cylinders have been in the form of a solid structure having an integral, one-piece working surface which is suitably engraved or etched to represent a number of patterns to be printed, for

example, several pages of a book. Whenever a change is required in the composition or layout of one of the patterns or one of the patterns is defective or damaged, it is necessary to replace the entire intaglio printing cylinder.

An intaglio printing cylinder must have a Working surface that is smooth, except at the intagliated or recessed portions thereof, and not interrupted, as by crack or gaps therein. Further, by reason of the high contact pressures used in intaglio printing, the structure forming the working surface of an intaglio printing cylinder must be strongly supported over its entire area. It has been found that the known arrangements for forming the Working surface of a typographic printing cylinder of a plurality of plates clamped or locked-up on the surface of a cylindrical support body cannot be applied to intaglio printing cylinice ders as such arrangements do not result in a working surface having the foregoing essential characteristics.

Accordingly, it is an object of this invention to provide a printing or like cylinder having a plurality of plates assembled together on the periphery of a cylindrical support body to constitute a working surface which is smooth and uninterrupted, or interrupted at most by Way of fine or hairline cracks at acceptable locations, and which is also capable of withstanding high contact pressures.

Another object is to provide an intaglio printing cylinder having such a smooth, uninterrupted and strongly supported working surface constituted by a plurality of plates which are assembled together in edge to edge relation on the periphery of a cylindrical support body and etched or engraved either before or after such assembly.

A further object is to facilitate the assembling together of a plurality of plates in edge to edge relation on a cylindrical support body and the clamping or lock-up of the assembled plates to constitute the working surface of a printing or like cylinder.

Still another object is to facilitate the removal of one or more of the plates assembled together in edge to edge relation to constitute the working surface of a printing or like cylinder, thereby to make possible the rapid replacement of any of such plates that are damaged or defective.

In accordance with an aspect of this invention, a printing or like cylinder is provided with a working surface constituted by a plurality of plates of sheet material formed to the curvature of the cylindrical peripheral surface of a support body on which the plates are assembled in edge to edge relation with each plate having side edges parallel to its axis of curvature that extend axially of the body, and the plates are held or locked-up in tight faceto-face engagement against the body surface with the side edges of each plate in precise abutting relation to those of adjacent plates by means including axially disposed gripping elements mounted on the body and engaging into the side edges of each plate at locations below the outer face of the plate and confining the full lengths of such edges at the outer face of the plate to locations precisely coinciding with those of the side edges of adjacent plates at their outer faces.

For the best performance of the invention, each of the side edges of each plate has recess means formed therein between the faces of the plate and disposed substantially from end to end of the edge, for example, in the form of a groove along such edge, and each side edge is further undercut between the groove or other recess means and the concave face of the plate so that gripping elements disposed axially on the support body can extend radially between the undercut portions of abutting side edges of adjacent plates and engage into the recess means thereof, for example, by means of oppositely directed flanges provided along each gripping element.

In accordance with another feature of this invention, the gripping elements extending axially on the support body are radially displaceable relative thereto so that, when the gripping elements are engaged into the side edges of each plate which are parallel to its axis of curvature, radially inward displacement of the gripping elements draws each plate tightl against the surface of the support body and causes the gripping elements to locate the side edges of each plate in precise abutting relation to those of adjacent plates. On the other hand, radially outward displacement of the gripping elements spaces their outer end portions from the surface of the support body and frees the side edges of each plate With respect to the gripping elements engaging therein 50 that the plate can be removed or disengaged therefrom, for example, by

lifting it off or by displacement of the plate in a direction parallel to its side edges in the case where the gripping elements have flanges therealong engaging in grooves extending from end to end of the side edges of the plates.

It is still another feature of this invention to apply vacuum to the plates for holding the plates tight against the surface of the support body where required either by the circumferential dimensions of the plates or by the flexing characteristics of the plates, for example, when the latter are formed of bendable sheet material deformed to the curvature of the surface of the support body. Further, when the axial dimensions of the individual plates are only fractions of the axial length of the working surface to be provided on the cylinder, so that a plurality of the plates are arranged with their circumferential edges in abutting relation to make up such axial length of the working surface, gripping elements may also be arranged circumferentially on the support body to engage into the abutting circumferential edges of adjacent plates for 10- eating and holding such edges and ensuring that the outer faces of the adjacent plates exactly coincide at their abutting circumferential edges.

In those cases where the support body also has circumferential gripping elements to engage into the corresponding abutting edges of adjacent plates, one or more of the circumferential gripping elements may be mounted for axial movement on the support body, thereby to permit engagement and release of the plates thereby, and the axial movements or displacements of the movable circumferential gripping elements may be coordinated with the radial displacements of the axially disposed gripping elements for engaging and releasing the plates.

The above, and other objects, features and advantages of the invention, will be apparent in the following detailed description of illustrative embodiments thereof which is to be read in connection with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a printing or like cylinder embodying this invention and having plates which constitute the working surface of the cylinder partly broken away to show the structure by which such plates are tightly held on the periphery of a support body;

FIG. 2 is an axial sectional view in a dimentrical plane of the cylinder, but on a scale larger than that of FIG. 1;

FIG. 3 is a fragmentary sectional view taken along the line 3-3 n FIG. 2, and shown on a further enlarged scale;

FIG. 4 is a further enlarged fragmentary sectional view illustrating the engagement of a gripping element into abutting side edges of adjacent plates forming the working surface of the cylinder;

FIG. 5 is similar to that of FIG. 4, but showing the gripping element displaced radially outward to release the plates;

FIG. 6 is a fragmentary sectional view illustrating the configuration of a side edge of one of the plates;

FIGS. 7a, 7b, 7c and 7d are perspective views respectively illustrating several stages in the production of the plates for forming the working surface of the printing or like cylinder;

FIG. 8 is a perspective view similar to that of FIG. 1, showing another embodiment of this invention;

FIG. 9 is an enlarged, axial sectional view taken along FIG. 14 is an enlarged view illustrating an intersection of axially and circumferentially extending gripping elements provided in the cylinder of FIG. 8 for securing the plates forming the working surface thereof to the underlying support body.

Referring to the drawings in detail, and initially to FIGS. 1 and 2 thereof a printing or like cylinder 10 embodying this invention is there shown to comprise a sup port structure 11 and a plurality of plates 12 assembled on the support structure to constitute the working surface of the cylinder. Support structure 11 may include a body 13 having a cylindrical periphery that constitutes a support surface for plates 12, and end flanges 15 secured to the ends of body 13, as by bolts 16, and having centrally located trunnions 17, by which the cylinder may be rotatably supported, projecting axially outward from the end flanges. Flanges 15 may have inwardly directed rims 18 extending over the end portions of surface 14 (FIG. 2) for axially confining plates 12 on cylinder 10.

' In accordance with this invention, each of plates 12 is pre-formed of sheet material formed to the curvature of support surface 14. For example, each plate 12 may be precut from thin bendable sheet metal deformed to the curvature of surface 14. Each plate 12 has bounding side edges 19 parallel to the axis of curvature of the plate to extend axially of surface 14 when plates 12 are assembled thereon in edge to edge relation to form, by their outer faces 20, the working surface of cylinder 10.

The plates 12 are circumferentially dimensioned to exactly circumscribe surface 14 when assembled thereon with axial side edges 19 of each plate in precise abutting relation to those of adjacent plates. Thus, for example, each plate 12 may be preformed with its circumferential dimension 0 (FIG. 7d), measured along outer face 20 between edges 19, as an exactly aliquot part of the circumference of the working surface to be provided on cylinder 10. When each plate 12 is to form the complete axial length of the working surface, as on the cylinder 10, the axial length a of each plate measured between its circumferential end edges 21 is precisely predetermined to be equal to the axial distance between rims 18 of flanges 15 so that such rims engage the end edges of the assembled plates for axially locating the latter on support surface 14.

Each of plates 12 is held in tight face to face engagement with support surface 14 and in precise abutting relation, at its side edges 19, with the side edges of adjacent plates, by means including gripping elements 22 extending axially on body 13 at the locations to be occupied by abutting side edges 19 of adjacent plates. Gripping elements 22 are intended to engage into side edges 19 of each plate 12 at locations below outer face 20 of the plate and to confine the full lengths of such edges 1Q, at outer face 20, to locations exactly coinciding with those of the side edges of adjacent plates at their outer faces 20 so that the resulting working surface of cylinder 10 will be free of gaps or cracks, other than very finefor hairline cracks, and perfectly cylindrical at the locations of the joints defined by the abutting side edges 1910f adjacent plates. In order to achieve the foregoing, each side edge 19 has recess means 23 (FIG. 6) formed therein between outer face 20 and the inner or concave face 24 of the plate, and each gripping element 22 has oppositely directed lateral projections or head portions 25 extending therefrom (FIGS. 4 and 5) to engage into recess means 23 of abutting side edges 19 of adjacent plates 12.

.As shown, recess means 23 in each edge 19 is preferably in the form of a groove extending continuously from end to end of the edge, and projections 25 are preferably in the form of oppositely directed flanges extending along the outer margin of each gripping element 22. Further, where each gripping element 22 projects radially outward from support surface 14,- as shown, each edge 19 is u de s t, as at 2. Q 5 and betwe n gr o e 23 and inner face 24 so that each gripping element can extend radially between undercut portions 26 of adjacent edges 19 to engage its flanges 25 in grooves 23 of such adjacent edges without obstructing the abutment of the edges at the portions thereof between grooves 23 and outer face (FIG. 4).

The assembling of plates 12 on support surface 14, and the replacement of individual plates, are facilitated by making gripping elements 22 radially movable with respect to body 13. Thus, as shown, gripping elements 22 are preferably in the form of flat blades extending axially in radial planes and being radially slidable in slots 27 (FIGS. 2 and 3) that are formed in body 13 and open radially outward at surface 14.

When gripping elements 22 are urged radially inward to the position shown on FIGS. 2, 3 and 4, the engagement of flanges in grooves 23 of adjacent edges 19 of adjacent plates 12 draws the latter into locations in which their concave inner faces 24 tightly engage support surface 14 and their edges 19 are in precise abutting relation. Further, the engagement of flanges 25 in the precisely mating grooves 23 ensures that the outer faces 20 of adjacent plates exactly coincide at their abutting edges 19 to provide a gap-free, smooth joint therebetween.

However, when gripping elements 22 are displaced radially outward, for example, from the position shown on FIG. 4 to that shown on FIG. 5, the plates 12 therebetween are moved radially away from surface 14, and the circumferential distance between the outer margins of adjacent gripping elements is increased, which tends to withdraw flanges 25 from grooves 23 in the opposed side edges of the plate located between the gripping elements that are thus displaced. The extent of the withdrawal of flanges 25 from grooves 23 is determinedby the amount of radially outward displacement imparted to gripping elements 22. The withdrawal of flanges 25 may range from mere loosening thereof in grooves 23, in which case the released plate can be removed or installed b dis placement thereof in a direction parallel to its edges 19, to complete withdrawal from grooves 23, as shown on FIG. 5, in which case the released plate can be lifted radially outward off flanges 25.

In the illustrated cylinder 10, gripping elements 22 are urged or forced radially inward by helical springs 28 (FIGS. 2 and 3) that are received in windows or openings 29 formed in each gripping element at locations spaced apart therealong, and also received in bores 30 extending axially through body 13 so as to be intersected by slots 27. The radially inner end of each spring 28 abuts against the radially inner edge of the respective window and the outer end of the spring seats against the surface of bore 30 so that each spring acts radially inward on the related gripping element.

In order to effect radially outward displacement of gripping elements 22, body 13 has axial bores 31 extending therethrough and opening into slots 27 along the radially inner perimeters of the latter, that is, radially below the gripping elements in such slots. Each of bores 31 is shown to communicate with a fitting or nipple 32 (FIGS. 1 and 2) mounted in one of end flanges 15 and through which compressed air, or other fluid under pressure, can be admitted to bore 31 to act radially outward in the respective slot 27 against a seal 33 (FIGS. 2 and 3) of rubber or the like provided along the inner margin of each gripping element.

The force exerted by the compressed air acting radially outward against a gripping element 22 may be only suflicient to effect slightly radially outward displacement of the gripping element against the contrary force of springs 28, in which case the gripping element can be manually displaced further in the radially outward direction to achieve the desired withdrawal of flanges 25 from grooves 23. Alternatively, the air pressure applied may be sufficient to fully compress springs 28 and thereby effect the displacement of the gripping element to its released position.

Although each bore 31 is shown to have an individual fitting 32 for introducing compressed air thereto, in which case each gripping element is individually displaceable to its plate releasing position, it is apparent that passages (not shown) may be provided in body 13 to establish communication between the bores 31 and thereby permit a reduced number of fittings 32 to be employed for supply ing compressed air simultaneously to all of the communieating bores 31.

By reason of the gap-free working surface defined by faces 20 of plates 12 and the absence of any ridges or steps at the precisely abutting edges 19 thereof, cylinder 10 is ideally suited to serve as an intaglio printing cylinder merely by having the patterns to be printed, engraved or etched into the Working surface of the cylinder formed by faces 20.

Such engraving or etching may be performed in the conventional manner on the working surface as a whole, that is, after the assembly of plates 12 on support body 13 of the cylinder. However, a particular advantage of the described cylinder 10 as an intaglio printing cylinder resides in the fact that it permits the engraving or etching of the individual plates 12 before the assembly thereof, and even when the plates are in flat or planar condition.

In order to ensure that the patterns engraved or etched into the several plates will precisely register with each other when the plates are assembled to form the working surface of cylinder 10, the plates 12 are preferably fabricated in accordance with the following procedure:

-A flat blank 12a (FIG, 7a) of thin bendable metal or other sheet material is provided for each plate 12 with dimensions a and c that are greater than the final dimensions a and 0, respectively, of the plate. The blank 12a, while flat or planar, is suitably engraved or etched with the desired pattern p and with locating cross-hairs h in precise register with the pattern. The etched blank 12a is microscopically indexed on an accurate drill fixture by sighting on cross-hairs h, and locating holes I are drilled through the ends of the blank beyond the portion of the latter which will form the final plate.

After holes I are drilled, the blank 12a is accurately positioned in a bending die, by locating pins received in holes I, and the blank is deformed, as shown on FIG. 7b, to the curvature of support surface 14. The deformed blank is then positioned in a holding fixture and accurately located by pins received in holes I while the side edge portions of the blank are accurately cut radially to its convex face along the broken lines 34 (FIG. 712) so as to have the final circumferential dimension c, after which the longitudinal edges of the blank parallel to its axis of curvature are accurately milled to form the grooves 23 and undercuts 26 therein. The resulting blank (FIG. 70) is transferred to another holding fixture in which the blank is located by pins engaging in holes 1 and the end portions of the blank are accurately cut-off along the broken lines 35 (FIG. 70) to provide the final axial dimension a of the completed plate 12 (FIG. 7d).

Although the steps of the above procedure have been described as being applied successively to a single plate, it is apparent that all of the engraved plates to form the working surface of an intaglio printing cylinder should be subjected to each step or operation before proceeding to the next step, thereby to facilitate the setting-up of each operation. It is also to be noted that, where desired, the initial bending of each blank to the curvature of support surface 14 may be omitted, or the blank may be deformed to have a radius of curvature greater than that of surface 14, in which cases, the urging of gripping elements 22 by springs 28 is relied upon to deform each plate gripped by elements 22, or to complete the deformation thereof, to the exact curvature of surface 14 when the plates are assembled thereon, In any event, springs 28 are sufficiently strong to hold each plate 12 tightly in face to face engagement with surface 14 in opposition to the centrifugal force acting on the plate during high speed rotation of cylinder 10. Gripping elements 22 engaging into the axially extending side edges 19 of each plate can be relied upon as the exclusive means for holding each plate tightly against support surface 14 only so long as the circumferential extent of each plate and the flexibility of its material do not combine to permit outward bulging of the plate between its edges 19 under the influence of centrifugal force. Where such bulging might occur, each plate is additionally held against the surface of the support body by gripping elements engaging into the circumferential edges of the plate and/or by vacuum applied to the concave inner face of the plate, for example, as in the cylinder 110 illustrated by FIGS. 8 to 12.

Cylinder 110 is shown to comprise a support structure 111 having a number of plates 112 assembled thereon in edge to edge relation both axially across the cylinder and circumferentially around the latter to form the working surface thereof. Each plate 112 may have axial and circumferential dimensions equal to one-quarter of the axial and circumferential dimensions, respectively, of the working surface to be formed thereby. Thus, if cylinder 110 is to constitute an intaglio or rotogravure printing cylinder for the production of books, each of plates 112 may be engraved or etched with the composition of a book page and the cylinder is operative to print sixteen pages during each revolution thereof.

Support structure 111 is shown to include a body 113 forming a cylindrical support surface 114 for plates 112 at the periphery of the body and having trunnions 117 projecting axially from its opposite ends by which the cylinder can be rotatably supported. End clamping rings 115 are axially movable on the opposite end portions of body 113 and have inwardly directed, annular rims 116 (FIG. 9) that extend over the end portions of support surface 114. Each of rings 115 has a number of, for eX- ample, four, equally spaced, hollow cylindrical guides 136 (FIGS. 9 and 10) projecting axially therefrom in the same direction as rim 116 and being slidably received in axial bores 137 opening at the adjacent end of body 113. Extending axially through each hollow guide 136 is an adapter 138 having a threaded inner end portion 139 (FIG. 9) screwed into a tapped hole at the bottom of bore 137. A helical spring 140 is positioned around each adapter 138 and bears, at its opposite ends, against shoulders on the adapter and guide 136 to urge the latter axially into bore 137, and thereby to urge end rings 115 axially toward each other. One or more of adapters 138 at each end of the cylinder further has an axial bore 141 opening at the outer end of the adapter and communicating with radial passages 142 opening into bore 137 beyond the inner end of guide 136. The inner end portions of bores 137 at each end of body 113 may be communicated with each other by passages 143 (FIG. 11), and the outer ends of adapters 138 may have removable sealing caps 144 (FIG. 9) thereon. Thus, when any one of the caps 144 is removed and compresed air or other fluid under pressure is supplied through bores 141 and 142 of the related adapter to the inner end portion of a bore 137, such compressed air is transmitted through passages 143 to all of the other bores 137 to act therein against the inner ends of guides 136 which form pistons moved axially outward against the force of springs 140. Each of guides 136 may carry seals 145 (FIG. 9) engaging the surfaces of the related bore 137 and adapter 138 to prevent the escape of compresed air therebetween.

As in the first described embodiment of this invention, plates 112 are each preformed of thin bendable metal or other sheet material deformed to the curvature of support surface 114 and have bounding side edges 119 (FIG. 8) parallel to the axis of curvature of the plate to extend axially of surface 114 when the plates are assembled thereon in edge to edge relation to form, by their outer faces 120, the working surface of the cylinder.

The means for holding each plate 112 in tight face to face engagement with support surface 114 and in precise abutting relation, at its side edges 119, withv the side edges of adjacent plates, includes gripping elements 12.2

extending axially on body 113 at the locations to be occupied by the abutting edges 119 of adjacent plates, and engaging into recess means 123 formed in edges 119 of each plate. As before, the recess means 123 in each edge 119 is preferably in the form of a groove extending continuously from end to end of the edge between outer face 120 and the inner or concave face 124 of the plate (-FIG. 12), and each edge 119 is further undercut between groove 123 and inner face 124 to permit each gripping element 122 to extend radially between such undercut portions of abutting edges 119 and to engage the oppositely directed flanges 125 disposed along the outer margin of the gripping element into recesses 123.

Further, as in cylinder 10, gripping elements, 122 are radially slidable in slots 127 formed in body 113 and opening at surface 114 thereof, and springs 128 are seated in Windows 129 of each gripping element 122 and in axial bores 130 (FIGS. 9 to 12) that intersect slots 127 to urge the gripping elements radially inward. Opening into each slot 127 along the inner margin therof is an axial bore 131 which, at one end of body 113, communicates with a fitting or nipple 132 by which compressed air can be supplied to act radially outward against a seal 133 along the inner margin of the related gripping element for urging the latter to its plate releasing position.

In the embodiment presently being described, the circumferential or end edges 121 of each plate 112 are also grooved, as at 146 (FIG. 13), and undercut to receive circumferential gripping elements mounted on body 113 at the locations to be occupied by edges 121 of the assembled plates. Thus, the fabrication of plates 112 can proceed in the manner described above with reference to plates 12, but with the additional steps of securing the plate 112 in a holding fixture which grips the previously grooved edges 119 for register, and holding the plate to the fixture by vacuum during the accurate grooving and undercutting of its end edges 121.

When the axial dimension of each plate 112 is onequarter of the axial length of the working surface on cylinder 110, as shown, the circumferential gripping elements may include a fixed gripping element 147 located at the axialcenter of surface 114, and two removable gripping elements 148 located axially midway between gripping element 147 and gripping elements formed by flanges 149 extending along the edges of rims 116 on clamping rings 115 (FIG. 9).

The central or fixed gripping element 147 may be formed by four equal segments of a ring secured, as by bolts 150, in an annular recess 151 cut into surface 114 and each having a generally T-shaped flange 152 extending therealong to project radially beyond surface 114 for engaging into grooves 146 in the abutting edges 121 at the axial center of cylinder 110.

Each of the removable circumferential gripping elements 148 may include four equal segments of a ring each having a relatively wide base 153 (FIG. 9) seating on the bottom of an annular recess 154 cut into surface 114 and a T-shaped flange 155 extending from base 153 to project radially beyond surface 114 for engaging into grooves 146 of the circumferential edges 121 that abut at the location of the respective gripping element 148. The segments of each gripping element 148 are removably held in the respective recess 154 by clamp segments 156 and 157 (FIGS. 9 and 14) which are secured, as by bolts 158, in recess 154 at opposite sides of base 153 and have flanges overlying the latter.

When installing plates 112 on cylinder 110, compressed air is supplied to one of the adapters 138 at an end of the cylinders, thereby to displace the ring 115 at such end in the axially outward direction, and clamping segments 157 and the segments of gripping element 148 are removed from recess 154. Further, compressed air is supplied to the fittings 132 of at least two axial gripping elements 122 to relieve the force of springs 128 therefrom. Then the grooved axial edges 119 of a plate are aligned with the flanges 125 of two of such elements 122 and the plate is displaced axially inward along the latter until a grooved circumferential edge of the plate is engaged and located by a flange 152 of the fixed gripping element 147. A segment of gripping element 148 is now installed in recess 154 with its T-shaped flange 155 engaging in the groove along the edge 121 of the plate remote from the fixed element 147, and a clamp segment 157 is bolted into recess 154 to lock the installed segment of element 148 in position. Another plate is then displaced axially along flanges 125 of the relieved gripping elements 122 until a circumferential edge of the plate is engaged and located by flange 155 of the installed segment of element 148. The foregoing procedure is repeated around the cylinder 110, whereupon the source of compressed air is disconnected from the adapter or adapters 138 so that springs 140 can urge clamping ring 115 axially inward and thereby cause engagement of its flange 149 into the grooves extending along edges 121 at the adjacent end of the working surface. Thus, plates 112 will beinstalled around cylinder 110 on the half of surface 114 at one side of fixed gripping element 147 and the same procedure is followed for installing plates over the other half of surface 114. When all of plates 112 are installed and located, all of fittings 132 are disconnected from the source of compressed air and the axial gripping element 122 are urged radially inward by springs 128 to draw the plates tight against surface 114.

As shown on FIG. 13, each of the removable circumferential gripping elements 148 may be replaced by a circumferential gripping element 148a including clamping segments 156a and 157a that are permanently secured in recess 154, as by bolts 158, and hold down the base 153a of each gripping element segment 155a while permitting axial movement of the latter between the clamping segments. Further, springs 159 are located in bores 160 extending axially in clamping segments 156a and act against bases 153a to urge the respective gripping element segments axially toward the adjacent end of the cylinder, that is, away from the fixed central gripping element 147.

When installing each plate 112 between fixed element 147 and each of the movable elements 148a, the axial gripping elements 122 intended to engage the axial edges 119 of the plate being installed are first displaced radially outward to the full extent possible either to permit the plate to be dropped radially inward onto flanges 125 of gripping elements 122 between gripping elements 147 and 148a, or to permit the plate to pass over the flanges of gripping element 1480 while being displaced axially along flanges 125 of elements 122 to a position between gripping elements 147 and 148a. Such extreme radially outward displacement of elements 122 may be effected manually While compressed air is supplied to the related fittings 132 to relieve elements 122 of the force of springs 128. After plates 112 have been installed over both halves of surface 114 at the oppoiste sides of fixed gripping element 147, the source of compressed air is disconnected from the adapter or adapters 138 at the ends of cylinder 110 and springs 140* then displace clamping rings 115 axially toward fixed gripping element 147. The force of springs 140 is greater than the force of springs 159 in each gripping element 148a. Thus, flanges 149 of rings 115 engage in the adjacent end edge 121 of adjacent plates 112 and shift the latter axially toward the center of the cylinder to act against flanges 155a of gripping elements 148a which are, in turn, shifted axially in opposition to the force of springs 159 to tightly engage the plates between fixed gripping element 147 and movable gripping elements 148a. Thereafter, the source of compressed air is disconnected from fittings 132 so that axial gripping elements 122 are drawn radially inward so that plates 112 are securely held by axial and circumferential gripping elements engaging in all four edges of each plate. By reason of the precise mating of the flanges of the gripping elements with the grooves 123 and 146 cut in the axial and circumferential edges of each plate, the abutting axial and circumferential edges of adjacent plates are accurately registered and the outer faces of the plates exactly coincide at the abutting edges thereof to ensure that the working surface of cylinder 110 is free of gaps and smooth at the locations of the joints between adjacent plates.

Body 113 of cylinder 110 is further provided with ducts opening at surface 114 and through which vacuum can be applied to the inner or concave faces 124 of plates 112 for further holding the latter tightly in face to face contact with surface 114 against the centrifugal force acting on the plates during high speed rotation of the cylinder. As shown on FIGS. 9 and 10, the ducts for applying vacuum may include an axial bore 161 extending through one of the trunnions 117 and adapted to be suitably connected, at its outer end, to a source of vacuum. Passages 162 (FIG. 10) radiate from the inner end of bore'161 to an annular passage 163 formed in the adjacent end portion of body 113 and which intersects bores 130. Finally, passages 164 (FIG. 12) extend outwardly from each bore at opposite sides of the gripping element 122 passing through such bore and open into grooves 165 formed within each area of surface 114 covered by a plate 112. Such grooves 165 may extend along and are spaced inwardly from the four edges of plate 112, as is apparent on FIG. 8, to ensure that the vacuum is applied to relatively large areas of the inner faces of the plates.

In order to prevent the loss of vacuum and the drawing-in of ink into the joints between the abutting edges of adjacent plates 112, a sealing strip 166 (FIGS. 12, 13 and 14), of rubber or the like, is recessed into the surface of body 113 between each groove 165 and the adjacent axial and circumferential gripping elements and is engageable by the inner face 124 of the plate gripped by the latter.

Further, as shown on FIG. 14, each axially extending gripping element 122 preferably has beveled cutouts 167 formed in its flanges 125 at the location of each of the circumferential gripping elements 147 and 148 to receive the similarly shaped ends of the flanges on the segments of elements 147 and 148. Thus, the flanges of gripping elements 122 have overlapping intersections with the flanges of the circumferential gripping elements to ensure secure gripping of each plate at its corners.

It will be apparent that, in each of the described cylinders 10 and 110, each plate 12 or 112 is held tightly in face to face engagement with the support surface 14 or 114 over substantially the entire area of the latter covered by the plate, either by the action of the axial gripping elements 22 alone, in the case of cylinder 10, or by the combined action of the axial and circumferential gripping elements and the applied vacuum, in the case of cylinder 110. Thus, the plates are strongly supported over their entire areas and can withstand the higher contact pressures associated with intaglio printing. When cylinders embodying this invention are employed as intaglio printing cylinders, the gap-free working surface which is smooth at the joints between adjacent plates'12 or 112 ensures that no ink or at most a hairline of ink will be retained in such joints following the wiping of the working surface, and further that the presence of such joints will not lead to rapid wearing of the rollers, belts, blades or the like used to wipe or clean the cylinder surface. Where the surface of the cylinder is wiped by a ductor blade, as at 168 on FIG. 1, such blade is preferably mounted at a small oblique angle with respect to the abutting axial edges of the plate to ensure a smooth cleaning action with minimum wear.

The plates are dimensioned or sized so that any hairlines of ink appearing on the printed matter as a result of hairline cracks between the plates are located where the printed matter is to be cut. For example, the plates 12 of cylinder 10 (FIG. 1) may form rows of postage or commercial stamps and, in that case, are sized to dis pose of any hairline cracks appearing between edges 19 of the plates at the locations of the rows of perforations formed between the stamp rows. Similarly, when plates 112 of cylinder 110 are intended to print respective pages of a book, such plates are sized so that any hairlines printed on the paper by reason of hairline cracks at the abutting edges of the plates will appear at locations where the printed paper will be cut into sheets.

If hairline cracks are located within the areas of the final printed matter, that is, do not appear at locations where the final printed product is cut or perforated, or if it is desired in any case to avoid the printing of hairlines of ink by reason of fine or hairline cracks between the abutting edges of the plates, such hairline cracks can be eliminated altogether by applying a suitable filling composition thereto.

Intaglio printing cylinders having their working surfaces formed of plates 12 or 112 fabricated and assembled together in accordance with this invention make possible the individual engraving or etching of the plates before assembly and also the individual replacement of any plate that is defective or damaged, thereby avoiding the necessity of replacing the entire cylinder when any portion of its surface is damaged or defective and consequently reducing the cost of intaglio printing.

The present invention may be advantageously applied to any other cylinders that require a gap-free, smooth working surface. For example, the cylinder or 110 may form the impression cylinder of a rotary printing press, in which case each of plates 12 or 112 will have a layer of fiber packing bonded to its outer face and trimmed along the edges of the plate to form a compressible working surface which is gap-free and smooth at the joints between abutting edges of the plates and which can withstand heavy contact pressures. If any portion of such working surface is damaged, it is only necessary to replace the related plate 12 or 112.

What is claimed is:

1. A printing or the like cylinder comprising a body having a cylindrical peripheral surface, a plurality of plates formed to the curvature of said surface and assembled thereon in edge to edge relation, each of said plates having bounding side edges cut radially to its convex face and extending parallel to the axis of its curvature, each of said side edges having recess means formed therein and disposed from end to end thereof between the faces of the plate, each of said side edges further being undercut between said recess means and the concave face of the plate, and gripping elements extending axially on said body to extend between the undercut portions of the adjacent side edges of adjacent plates, said gripping elements having oppositely directed projections extending therefrom and engaging into said recess means of said adjacent side edges to position said plates, said gripping elements being displaceable radially with respect to said body to draw the plates engaged thereby into locations in which their concave faces engage said surface and their adjacent side edges are in precise abutting relation.

2. A printing or the like cylinder according to claim 1, said recess means in each of said edges being in the form of a continuous groove extending from end to end of the related edge, and each of said projections of said gripping elements being in the form of a flange extending therealong so that, when said gripping elements are displaced radially outward with respect to said body, said plates are spaced from said surface of the body and can slide relative to said flanges for engagement and disengagement therefrom.

3. A printing or the like cylinder according to claim 1, further comprising yieldable means forcing said gripping elements radially inward with respect to said body, thereby to draw said plates engaged thereby into said locations, and means operative to overcome the force of said yieldable means so that the gripping elements and said plates thereon can be displaced radially outward for releasing said projections from said recess means.

4. A printing or the like cylinder according to claim 3, said body having radial slots therein opening outwardly through said surface and having said gripping elements radially slidable therein, said yieldable means including springs acting on said gripping elements in said slots, and said means operative to overcome the force of said yieldable means including ducts in said body opening into said slots radially below said gripping elements for supplying fluid under pressure to act in said slots against said gripping elements in opposition to said springs.

5. A printing or the like cylinder according to claim 3, said body having radial slots extending axially therein and opening outwardly through said surface, said body further having axially extending bores therein which are intercepted by said radial slots, said gripping elements being constituted by elongated blades slidable radially in said slots and having windows in said blades, said yield able means including springs located in said windows of each blade within said axially extending bore which intercepts the respective radial slot, and said means operative to overcome the force of said yieldable means including ducts in said body opening into said slots radially below the blades slidable therein for supplying fluid under pressure to act in said slots against said blades in opposition to said springs.

6. A rotary printing or like cylinder comprising a body having a cylindrical peripheral surface, a plurality of plates of resilient hard sheet material of substantially uniform small thickness formed to the curvature of said surface and assembled thereon in edge to edge relation, each of said plates having opposite side edges which extend axially of said surface and respectively comprise outer edge portions that bound the outer face of the plate and mate with such edge portions of the adjacent plate or plates, and means normally holding said plates in tight face-to-face engagement with said surface with said outer portions of their adjacent side edges in precise abutting relation so that their outer faces form a rigid cylindrical surface that is free of gaps other than hairline cracks at said abutting edge portions, each of said side edges being undercut laterally along and beneath its said outer edge portion, said holding means including gripping elements mounted on said body and disposed axially therealong in the spaces between the undercut portions of said adjacent side edges, said undercut portions and said gripping elements being formed with laterally interfitting parts normally engaged tightly together to hold said edges tightly in place, the said gripping elements engaged with each plate and the plate thereon being displaceable radially outwardly relative to said body to an outward position thereof in which said parts are laterally disengaged so that the plate is readily removable and replaceable.

7. A cylinder according to claim 6, said interfitting parts comprising grooves recessed laterally in and extending from end to end of the respective undercut portions of said edges and respective lateral flanges on said gripping elements engaging into substantially the entire lengths of said grooves.

8. A cylinder according to claim 7, said body having slots extending radially over the length of and opening radially outward through said body surface, said gripping elements having the form of blades respectively fitting along and slidable radially in said slots and projecting radially therefrom to terminate in said flanges, said hold ing means including yieldable means acting on said blades to constrain them radially inward to normal gripping positions, and means in said body operable to displace said blades radially outwardly against the force of said yieldable means.

9. A cylinder according to claim 6, said holding means further including means inside said body for constantly exerting upon each of said gripping elements a force constraining the same radially inward to normal gripping position, and means inside said body operable to displace each of said gripping elements radially outwardly against the force of the related force exerting means.

10. A cylinder according to claim 6, said body having axially disposed slots opening radially outward through said body surface and said axially disposed gripping elements having the form of blades slidable radially in said slots and projecting therefrom to terminate in said parts thereof, said holding means further including yieldable means acting on said blades to constrain them radially inward to normal gripping positions, and means operable to displace said blades radially outward against the force of said yieldable means.

11. A cylinder according to claim 6, said body having axially disposed slots opening radially outward through said peripheral surface and said axially disposed gripping elements having the form of blades slidable radially in said slots and projecting radially outward therefrom to terminate in said parts thereof, said holding means further including spring means acting on said blades inside said body to constrain them radially inward to normal gripping positions, and means for supplying fluid under pressure to said slots and against inner portions of said blades therein so as to displace said blades radially outwardly against the force of said spring means.

12. A cylinder according to claim 6, the outer faces of said plates having intaglio printing patterns formed therein and together constituting a cylindrical intaglio printing surface.

13. A cylinder according to claim 6, said holding means further including ducts in said body opening through said body surface at locations spaced inside the edges of the respective areas thereof covered by said plates, for applying vacuum to the inner faces of said plates to further assure tight face-to-face engagement thereof with said surface.

14. A cylinder according to claim 13, said ducts having widened end portions recessed in said body surface to increase the distribution of vacuum applied to the plates, and sealing means on said body surface engaging said inner faces between said widened end portions and said gripping elements to prevent the vacuum from drawing ink between the abutting edge portions of adjacent plates.

15. A cylinder according to claim 6, each of said plates having opposite curved edges which extend circumferentially of said body surface, each of which has an outer edge portion bounding the outer face of the plate and is under-cut laterally along and beneath such outer portion, and said holding means further including gripping elements mounted on and disposed circumferentially about said body in engagement with the undercut portions of said curved edges, these gripping elements and undercut portions also being formed with laterally interfitting parts normally engaged tightly together to hold said curved edges tightly in place, some of said circumferentially disposed gripping elements being displaceable axially along said body relative to another or others of them for respectively constraining and releasing said plates therebetween.

16. A cylinder according to claim 15, said holding means further including means inside said body for constantly exerting upon certain of said axially displaceable elements a force constraining said circumferentially disposed gripping elements axially against said plates, and

means inside said body for constantly exerting upon each of said axially disposed gripping elements a force constraining the same radially inward to normal gripping position, and fluid pressure responsive means inside said body operable to displace said certain elements axially away from said plates, and to displace said axially disposed gripping elements radially outwardly, against the respective forces of said force exerting means.

17. A cylinder according to claim 15, said interfitting parts comprising a straight groove recessed laterally in and extending from end to end of the undercut portion of each of said side edges, a curved groove recessed laterally in and extending from end to end of the undercut portion of each of said curved edges, respective straight lateral flanges on said axially disposed gripping elements engaging into substantially the entire lengths of said straight grooves, and respective curved lateral flanges on said circumferentially disposed gripping elements engaging into substantially the entire lengths of said curved grooves.

18. A cylinder according to claim 15, said holding means further including ducts in said body opening through said body surface at locations spaced inside the edges of the respective areas thereof covered by said plates, for applying vacuum to the inner faces of said plates to further assure tight face-to-face engagement thereof with said surface.

19. A cylinder according to claim 18, said ducts having widened end portions recessed in said body surface to increase the distribution of vacuum applied to the plates, and sealing means on said body surface engaging said inner faces between said widened end portions and said gripping elements to prevent the vacuum from drawing ink between the abutting edge portions of adjacent plates.

20. A rotary cylinder according to claim 15, further including means to urge said axially disposed gripping elements radially inward and said circumferentially disposed gripping elements axially one toward another, for securing said plates on said body, and means operative to urge said axially disposed gripping elements radially outward and said circumferentially disposed gripping elements axially one away from another for permitting release of said plates from said gripping elements.

References Cited UNITED STATES PATENTS 901,873 10/1908 Brubaker 29124 1,357,341 11/1920 Novotny 10l378 1,209,736 12/ 1916 Lueckenbach 29124 1,928,161 9/1933 Wood 101378 2,060,082 11/1936 Johnson et al. 101-378 2,424,170 7/1947 Huck 101-378 3,001,472 9/1961 Parrish 101-378 3,180,007 4/1965 Gartz 29-124 2,261,305 11/ 1941 Stephenson 101378 FOREIGN PATENTS 609,145 11/ 1960 Canada.

371,138 9/ 1963 Switzerland.

ROBERT E. PULFREY, Primary Examiner J. R. FISHER, Assistant Examiner 

